Exhaust mufflers, as used in association with material handling trucks, usually extend vertically from the engine and are often located in a position where they can accidentally be contacted by the operator. To prevent injury to the operator from the heated muffler, it is desirable to provide a heat insulating cover for the muffler.
As the muffler on a material handling truck may frequently come in close proximity to flammable materials, such as paper cartons, bales of combustible materials, and the like, it is desirable to reduce the temperature of the exhaust gases being discharged from the muffler in order to minimize any potential fire hazard.
Attempts have been made in the past to utilize an outer heat shield in association with a muffler, as disclosed in U.S. Pat. No. 4,265,332. In the heat shield, as disclosed in the aforementioned patent, a metal shield is spaced outwardly of the muffler body and is tapered, in the area of the muffler outlet pipe to a smaller cross sectional area, thus providing a venturi so that air will be drawn through the space between the shield and the muffler, both by convection and aspiration, to reduce the temperature of the gas being discharged from the muffler.